[SR-Users] Kamailio 5.0 - B2BUA

[Alex Balashov]

Hi,

I wanted to raise the possibility of an inline signalling-only B2BUA 
component to Kamailio.

I know that's an extremely poor fit for Kamailio, and not at all what 
it's supposed to do. And there are many things about the OpenSIPS B2BUA 
module that reveal how awkwardly it is situated, as a square peg in a 
round hole. I myself am philosophically opposed to a B2BUA in Kamailio 
to the threshold of physical violence.

However, the reason I bring it up for discussion is that there are very 
few viable, high-performance signalling-only B2BUA alternatives that are 
FOSS. There is enormous demand for a B2BUA, mainly for topology 
concealment purposes, from the short-duration traffic industry, which 
many users of Kamailio deal with. It's why a lot of them end up going to 
OpenSIPS; they need the B2BUA, and prefer to consolidate on one OpenSER 
brand.

Anyone who has tried to run high-CPS traffic through the existing FOSS 
signalling-only B2BUAs out there situated in front of Kamailio has 
discovered, sometimes in a very financially painful way, that:

- FreeSWITCH falls over at around +/- 300 CPS.

This is with RTP relay disabled -- signalling-only. It requires 
horizontally scaling a large number of FreeSWITCH boxes to meet a 
capacity requirement of, say, 2000 CPS, which is unfortunate given the 
favourable proposition offered by Kamailio for the infrastructure unit 
economics. In other words, it's ironic to have to build a fleet of 10 
FreeSWITCH boxes for the 1% problem of topology concealment when 
Kamailio can otherwise churn through 2000 CPS with no issues.

- SEMS' 'sbc' module is a good candidate and can handle the load, but 
Frafos offers practically no support for it, with all efforts focused on 
their commercial ABC SBC product. That's very understandable, but just 
not practical given the high technical knowledge SEMS requires to deploy 
and maintain in this capacity.

- None of the other userspace B2BUA folk traditions can handle the load.

So, like I said, I personally recoil in shock and horror at the idea of 
introducing a B2BUA into something that was designed to be anything but 
a B2BUA. But, there is a huge market opportunity for this functionality 
in North America, and at the moment, users who need it are mostly ending 
up in OpenSIPS land.

-- Alex

-- 
Alex Balashov | Principal | Evariste Systems LLC
303 Perimeter Center North, Suite 300
Atlanta, GA 30346
United States

Tel: +1-800-250-5920 (toll-free) / +1-678-954-0671 (direct)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/